1. Field
An embodiment of the present invention relates to an apparatus for the optical communication.
2. Background
A multi-source agreement (MSA) accessible as “CFP MSA Hardware Specification Revision 1.4” in the internet, <http://www.cfp-msa.org>, has designed an optical transceiver implemented with an optical multiplexer/de-multiplexer and optical transmitter/receiver. The optical transceiver designed therein realizes the optical communication with the transmission capacity of 40 Gbit/s by multiplexing/de-multiplexing four optical signals each having the transmission speed of 10 Gbit/s; or an excellent transmission capacity of 100 Gbit/s by multiplexing/de-multiplexing four optical signals each having the speed of 25 Gbit/s.
Such an optical transceiver following the CFP-MSA above has two type of arrangements, one of which is called as the integrated type where the optical multiplexer and the optical de-multiplexer are integrated with the optical transmitter and the optical receiver; while, the other called as the discrete type divides the optical transmitter and the optical receiver from the optical multiplexer and the optical de-multiplexer. The integrated type may make the housing of the optical transceiver in compact because the discrete type needs a space to wire inner fibers coupling the optical multiplexer/de-multiplexer with the optical transmitter/receiver. On the other hand, the integrated type inherently has disadvantages in points that, when at least one of optical transmitter or the optical receiver falls into trouble, the whole components of the optical transmitter/receiver and the optical multiplexer/de-multiplexer are necessary to be replaced, which drastically increases the production cost of the optical transceiver. The discrete type may replace only one component falling into trouble.
The discrete type is necessary to set a plurality of inner fibers within the housing as securing the minimum bending curvature of the optical fiber. Moreover, each of the inner fibers accompanies therewith an optical connector to be mated with the optical multiplexer/de-multiplexer or the optical transmitter/receiver, and the process to assemble the inner fiber with the optical connector is necessary to estimate the process tolerance in a length of the processed inner fiber. Then, the housing of the optical transceiver is inevitable to be widened in the inner space thereof, and the space for distributing the inner fibers are, for instance, between the circuit board on which electronic components are mounted and the housing, in other words, the space under the circuit board.
Because the electronic components on the circuit board, in particular, the active electronic devices generally generate heat, the optical transceiver provides heat dissipating paths from the electronic components to the housing. Typical paths are thermal blocks put between the circuit board, in particular, portions of the circuit board where the active devices are mounted, and the housing. The inner fibers need to be distributed to escape from the thermal block, which inevitably results in the condition to reduce the process tolerance of the assembly of the inner fibers with the optical connector. Thus, both the integrated type and the discrete type have disadvantages peculiar to the respective types.